A low-cost high-entropy porous CrO/CrN/C biosensor for highly sensitive simultaneous detection of dopamine and uric acid

•Low-cost and high-entropy CrO/CrN/C biosensor was fast prepared by mechanochemistry.•High-entropy endows biosensor abundant interfaces and high dispersed sensing sites.•CrO/CrN/C structure greatly enhances biosensor conductivity and signal transfer.•Biosensor shows ultra-lower LOD for DA (10.65 nM) and UA (17.54 nM), simultaneously.•CrO/CrN/C shows high anti-interference, reproducibility and stability for DA/UA detection.